Swift response. Taylor Swift has forced Apple Music to back down on its non-payment policy during the free trial period. Photo: Getty Images

Music streaming allows you to listen to music directly via the internet through your computer, mobile phone and other devices. The listener "streams" a song or album in real-time rather than buying it for keeps and storing it on their computer. It's like Netflix, but for music.

Who are the major players?

Advertisement

The two biggest existing players in music streaming are Swedish company Spotify and US company Pandora. Others include French company Deezer, Google Play, Samsung's Milk app and local players JB Hi-Fi and Guvera. There are 18 currently available in Australia. They each have vast music libraries to browse, with the major players boasting around 30 million tracks and counting.

What are the main differences between them?

Some of these platforms, like Spotify's premium service, offer music "on demand", allowing you to listen to whichever track or album you want to. Others, such as Pandora, do not offer on-demand but create tailored playlists based on what music you like. Most streaming services also offer curated content, such as playlists in particular genres or compiled by guest artists.

How much do they cost?

Some services, such as iHeart Radio, are free and supported wholly by advertising. Others are subscription-only, such as the recently relaunched TIDAL streaming service, owned by US rapper Jay-Z. A TIDAL subscription starts at $11.99 per month. Spotify and Pandora have "freemium" streaming services, which offer both a premium, paid subscription service and an ad-supported service with restricted content or features.

So What is Apple Music?

Apple Music is a revamped version of Apple's existing music services – including the iTunes store and iTunes Radio – combined with some new goodies. This includes Beats1, a live internet radio station broadcast 24/7 from New York, Los Angeles and London. The streaming service will include both on-demand music and curated playlists. The iPhone's voice search feature, Siri, will know Apple Music back to front – for instance, if you ask her to play number one hits from the '90s (please don't), she'll serve them up for you right away. Like many of its rivals, it will also suggest new music based on your listening habits.

Why is Taylor Swift on Apple Music, but not on Spotify's 'freemium' service?

Advertising generates less revenue per listener than paid subscriptions. Spotify pools the revenue together before doling out royalties to record companies.

Spotify argues that without a free, ad-supported tier to draw listeners in, it would not have the 20 million paid subscribers it boasts today.

Swift, Jay-Z's TIDAL backers and other critics argue the freemium model devalues artists' work and that paid subscriptions must be promoted for the future.

Music streaming has been around for years, so why is Apple Music grabbing attention?

One problem with music streaming to date, content creators say, is that it hasn't reached big enough scale to generate meaningful returns for them.

The International Federation of the Phonographic Industry, which represents the record industry worldwide, says streaming accounted for just 14 per cent of total music revenue last year. Downloads of music tracks, and of course physical music sales of CDs and records, made up the rest.

However analysts believe Apple's brand power, gigantic customer base and existing relationships with record companies may finally bring music streaming into the mainstream.

Can Apple Music finally help musicians make a buck?

It's too early to say whether Apple can deliver on its promise to create a sustainable "ecosystem" in support of musicians. Industry insiders are saying Apple has the best chance yet at giving the industry a much-needed boost – not just because it may raise the profile of streaming in a big way but because it is supporting the paid subscription model. Apple Music's arrival could also prompt services such as Spotify to rethink their "freemium" options, which some in the industry would welcome. This mightn't mean getting rid of free options entirely, but adding further restrictions on content or features would encourage more users to pay.

Whichever way things pan out, an industry that has been struggling to reshape itself in the wake of digital disruption could be set for yet another major shake-up in coming months.